Just in time for the closing rush of the presidential election, MSNBC is shaking up its prime-time programming lineup, removing the long-time host -- and one-time general manager of the network -- Dan Abrams from his 9 p.m. program and replacing him with Rachel Maddow, who has emerged as a favored political commentator for the all-news cable channel.

The moves, which were confirmed by MSNBC executives Tuesday, are expected to be finalized by Wednesday, with Mr. Abrams's last program on Thursday. After MSNBC's extensive coverage of the two political conventions during the next two weeks, Ms. Maddow will begin her program on Sept. 8.

MSNBC is highlighting the date, 9/8/08, connecting it to the start of the Olympics on 8/8/08, as a way to signal what the network's president, Phil Griffin, said "will be the final leg of the political race this year." He added, "We making that Rachel's debut."

Mr. Abrams, who is well liked at MSNBC, is expected to remain at both that network and at NBC News, where he is the chief legal correspondent. He will also serve as an anchor during some of MSNBC's daytime coverage, as well as a substitute host on NBC's "Today" show, Mr. Griffin said.

The last broadcast of Abrams' "Verdict" will air Thursday.

Abrams, the network's former General Manager, told the Times that he understood the decision.

"Putting my general manager's hat back on, considering where the network is right now, it is actually the right call," he said.

Almost immediately, Keith Olbermann took to DailyKos to celebrate the news, brag about his involvement in the decision — "Yes, I had something to do with it," he wrote — and remind readers that though Maddow's rise at the network was quick ("less than five months between first paid appearance and own show"), his was quicker ("I believe I still hold the MSNBC record: I came back to guest host for three days in 2003 and 39 days later I had a contract to do the 8 PM show.").